FAQ on Fire Retardant Impact on Livestock and Irrigated Pasture

Question

If fire retardant was used on irrigated pastures I manage, could it have negative consequences I should be aware of for livestock, forage, or other?

Potential Risks

• There are no known studies on the impacts of fire retardant on livestock after use on grazing lands. This information is representative of the best available knowledge and inference. For further information on this you can refer to the ecological risk assessment of wildland fire-fighting chemicals and long-term fire retardants. See reference section.  
• Components of fire retardant are organic compounds, including inorganic nitrogen and phosphorous. No PFAs (Per- and polyfluoroalkyl substances) are intentionally added to wildfire fighting foam. 
• The amount of risk may depend on the amount and concentration of fire retardant applied. For more information on specific retardants, refer to the References/Citation section of this document (1). 
• While nitrogen and phosphorus are deliberately applied to pasture as fertilizer as part of typical management, there may be risks to livestock and pasture when these are applied as part of fire retardant because of the timing and potential concentrations.  
• Direct impacts to livestock are relatively low: provided livestock are not hungry or salt deficient when returned to treated pastures, the likelihood of them consuming enough to cause problems is low. 
• Indirect risks to livestock and pasture include increasing soil salt content, elevated nitrogen and/or phosphorus levels in soil, and nitrate poisoning in ruminants because of uptake of nutrients by stressed plants. All of these can be mitigated with testing (see below). 
• The red color of the flame retardant is iron oxide. This form of iron is not readily available if ingested. Signs of iron toxicity, while uncommon, may lead to digestive signs and liver failure (2,3). 

Actions You Can Take

• Test water supplies.
  • If there are any questions, have the water tested by a certified lab such as Ward Labs Water Analysis – Ward Laboratories, Inc or the CSU Soil, Water and Plant Testing Labroatory. CSU has developed a water quality interpretation tool that can be used with test results: CWI Water Quality Interpretation Tool. 
  • Additionally,  
    • Clean out all potentially contaminated troughs 
    • Test ponds, springs and wells. 
• Test forage and soil. 
  • You can test forage by sending a sample directly to a laboratory such as Servi-tech, Ward Laboratories, CSU Soil, Water and Plant Testing Labroatory or Weld Laboratories (for equine specific options). Costs for feed analysis vary between $13 and $40 depending on tests required.  
  • You can test soil via a soil test which start around $17.35 at a lab such as Ward labs (Soil & Soil Health Analysis – Ward Laboratories, Inc.) or CSU labs (Soil, Water and Plant Testing Laboratory – Soil Testing Lab). 
  • If you need help with soil or forage testing, contact your local CSU Extension office.  
• Defer grazing if possible: Keep animals off until the next season and allow the plants to utilize the fertilizer; this will increase plant health and yields in the future.  
• If deferred grazing is not possible, follow the above precautions of testing.  
• If possible, allow for a couple of rains or irrigations to wash off the retardant.  
• If you must graze fields, make sure there is clean water available for livestock. Closely watch animals for signs of sickness. Call your veterinarian if symptoms are noticed (4). 
  • Loss of appetite 
  • Change of habits, listless behavior 
  • Staggering or weakness, tremors 
  • Respiratory distress 

References

1. USDA Forest Service information on currently used fire retardants:  https://www.fs.usda.gov/rm/fire/wfcs/long_term_fire_retardants.php 
2. Smith, B. P. (Ed.). (2014). Large Animal Internal Medicine-E-Book: Large Animal Internal Medicine-E-Book. Elsevier Health Sciences. 
3. Stern, L. (2025). Merck Veterinary Manual Professional Version. https://www.merckvetmanual.com/toxicology/toxicoses-from-human-vitamins-minerals-and-dietary-supplements/toxicoses-in-animals-from-human-multivitamins-and-supplements?query=iron%20toxicity%20cattle. 
4. Stevens County Conservation District. Fire Retardant Impacts to Livestock. https://wpcdn.web.wsu.edu/wp-extension/uploads/sites/2128/2022/08/Fire-Retardant-Livestock-SCCD.pdf 
5. Ecological Risk Assessment of Wildland Fire-Fighting Chemicals: Long-Term Fire Retardants – https://www.fs.usda.gov/rm/fire/wfcs/documents/2021%20EcoRA-Retardants-Nov2021-final.pdf  

Disclaimers

No endorsement of products mentioned is intended, nor is criticism implied of products not mentioned. 
 
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of the product to the exclusion of others which also may be available, nor does it intend discrimination or criticism of products or providers that are mentioned or not mentioned. In addition, CSU Extension assumes no liability for harvesting or use of  
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